Paint and lacquer spray gun



Mrch 25, 1930. F. A. TITTEMORE ET AL PAINT AND LACQUER SPRAY GUN FiledFeb. 13. 1925 L .NN

Patented Mar. 25, 1930 UNITED STATES PATENT OFFICEv FRANK A. TITTEMOREAND CHARLES S. RENWICK, OF RICHMOND, CALIFORNIA, AS- SIGNORS TO HOPKINSSPRAY EQUIPMENT COMPANY, 0F SAN FRANCISCO, CALI- FORNIA, A CORPORATIONOF NEVADA PAINT AND LACQUER SPRAY GUN Application led February 13,`1926. Serial No. 88,022.

Our invention relates to spray-guns in genl eral, and particularly to agun adapted for the spraying of aint and lacquer.

The general o ject of our invention is to 5 eliminate some of theobjectionable features of spray guns in present use; which object weattain by providing a gun possessing, by reason of its novelconstruction, certain ad- `vantages which may be divided and considuFirst, the production of a fan or fish-tail spray, by means of twoopposing, flattening air-jets, so disposed with relation to the issuingmaterial jet as` to perform the additional functions of siphoning andatomizing, without an additional or third air-jet, thereby effectingeconomy in air consumption.

Second, providing for the timely successive openin of thematerial-control and the air control, y an aligned disposition of theirassemblies, which ylelds an advantage in simplifying the structure, andreducing the weight of the gun.

Third, providing for the easy removal of repairs and substitution, andits ready replacement in the gun.

' Fourth, providinor for a similar removal and replacement ofj bly, fora like purpose.`

, These, and other objects, including features of adjustment, willhereinafter be fully set forth in detail, after a description of the gunhas been given in connection with and by reference to the accompanyingdrawings,

in which a preferred form of our gun is disclosed, it being understoodthat changes in details may be made without departing from 4 the spiritof our invention as defined by the claims' hereunto appended.

In the drawings Fig. 1 is a longitudinal section of our gun. Fig. 2 is asection on the line 2-2 of Fig. 1,

the trigger being' omitted. Fig.'3 is a section on the line 3-3 of Fig.1,`all interior parts being omitted.

Fig. 4 is a longitudinal section, enlarged, of the spray-head nozzle,the material-controlling plunger being omitted.

1 Fig. 5 1s a section on the line 5-5 of Fig. 4.

the material plunger-assembly for necessary the air plunger-assem-A Fig.6 is a modication of the spray-head nozzle.

The body casting of the gun, comprises the barrel -41, the handle stock2 and the suspension hook 3. The forward end of the barrel is formedwith a bore 4 which constitutes the material chamber, entrance to whichis had through a passage 5 in a nipple 6 formed on the lower side of thebarrel, said nipple being adapted for connection with a source ofmaterial (not shown) which may be under gravity head or other pressure,or under no other pressure than that due to the suction of induction orsiphoning. y,

The forward end of the material chamber 4 is internally threaded andterminates in a flange 7 which is threaded both internally andexternally.

Into the flange 7 and the material chamber 4 is'screw-fitted the sprayhead or nozzle 8, which is further locked by a cap 9 screwed upon theflange 7. The forward end of the bore of the nozzle 8y is coned asusual, and its outlet orifice -or port terminates in a nipple 10 whichprojects in the axis of aconcavity 11 with which the forward extremityof the nozzleis provided.

The nozzle' 8 is formed with an encircling groove 12, from which twoair-ducts 13 separated by 180 degrees lead forwardly in the nozzle wallparallel for a portion of their length, with the axis of the nozzle; butin the tipof said nozzle, said ducts converge and open out into theconcavity 11 in lines which if projected are inclined to and intersect,from opposite sides, a hypothetical projection of the nipple 10,andpreferably as close to the extremity of said nipple as possible.

See Fig. 4.

In the upper portion of the barrel l 1s the air passage 14 which at itsforward end com- `municates with the groove 12of the nozzle 8, and atits rear end communicates with a port 15 in a valve-seat member 16removably fitted within the rear end or heel of the barrel 1. Thismember 16 removably Acarries'a nipple 17 by which connection is madewith a suitable source (not shown) of air under pressure.

The member 16 is best removably secured 8 to the passage of thematerial.

inthe barrel by threading its forward end 16 in the barrel bore and saidend is recessed to carry a packing 18. Back of the port 15 said member16 is formed with a valve seat 19. Y

2O is the air controlling valve operating upon the valve seat 19. Thevvalve has a plunger or stem 21 which projects rearwardly and is fittedwith a spring 22 shouldered between theA nipple 17 and the valve. Thevalve stem 21 also projects forwardly, passes slidably through thepacking 18, and terminates within the trigger opening 23, of the barrel;and said forward end carries a regulating connection in the form. of acup 24, the latter being adjustably secured to the stem' as, forexample, by being threaded thereon.

Within the cavity of the cup 24 is freely housed the head 25 of thematerial-plunger stem 26 the forward end of which controls the outlet ofthe spray head or nozzle 8.

The plunger stem 26 passes through a packing gland 27 removably secured,as by screw fitting, in the barrel 1, and the head of said gland isproperly formed for the reception of a tool adapted to remove said glandwhen necessary. A spring 28 lying between a collar 28 and a guide 28controls said plunger stem.

29 is the trigger, fitting upwardly into the opening 23 of the barrel.The upper portion of the trigger is forked freely over the plunger stem26, the forks 29 passing in front of and in normal contact with theregulating cap 24, and said forks are removably pivoted in the barrel at30.

Before pointing out in detail the several features of novelty in ourgun, it will be well to describe in general terms its operation, inorder that its structure may be reviewed, and more perfectlyappreciated.

The material to be sprayed, say, for example, paint or lacquer, entersat the connection 6, and the air enters at'connection 17. When thetrigger 29 is pressed back, its forks 29, by contact with the cup 24,opens the valve 20, so that the air will pass through port 15, passage14, groove 12, and ducts 13, from the latter of which it will bedischarged.

The trigger 29 will also, by continuance of movement, contact with thehead 25 of the .plunger stem 26, and move said stem back to open thedischarge orifice of thespray nozzle The first feature to -whichattention is directed concerns the spray-'j et and the novel meansherein disclosed for producing it.

Generally speaking the principal feature of spray guns is the atomizingheal ofthe gun. Three principles of atomizing are, at present, in use,namely, the cross-fire atomization, where the material nozzle and theair nozzle are at right angles or nearly so; the

center atomization where the air nozzle sur- Arounds the material nozzleand the air pas' sage is parallel with the material nozzle; and the oldmethod of atomization under eXtreme pressure of the material itself,such as the whitewash spray system.

In guns at present on the market, sprays are produced commonly known asfan sprays, fish-tail sprays and fiat sprays, all these terms referringto the same shape of spray. Sprays of this shape are produced on theprinciple of center atomization combined with two side jets of airstriking the spray jet at approximately half an inch from the outlet andthus flattening it out. This procedure, therefore, involves three jetsof air, one for siphoning effect and atomization, and two for theflattening of farming operation.

In our gun the principle of center atomizaj tion is omitted, since weuse no air jet surrounding and parallel Iwith the material jet for thepurpose of siphoning and atomizing. Both these effects are produced inour gun b the two side air jets from the ducts 13, whic effects are theresult of striking the material jet at an acute'angle and preferably ata point as close to the issuing plane of the material j et as possible.Thus we combine by the disposition and use of the two side air-j etsonly, the siphoning and atomizing effect and the flattening outl of thespray into a fan or fishtail shape, thereby reducing the consumption oair. v

It will be noted also that our nozzle 8 is capable of being rotatablyadjusted in order operation is usually accomplished by a single Itrigger control of air valve and material plunger which are not,however, in alignment. It is common practice to eithe` have the airvalve below or above the line of the material plunger, thus involvinghaheavy and cumbersome body casting, as well as a trigger contact atdifferent points.

In our gun we have been able to align the two plungers by means of thecup 24 on the air qolunger stem 21 and the head 25 on the plunger stem26, the relation o'f said cup' and said head being such as shown clearlyin Fig. 1, that upon pulling the trigger 29 its forks 29 will contactwith the air plunger cup 24 slightly before they will reach and contactwith the head 25.

A third feature of novelty will now be mentioned. In guns in which theacking gland of the material plunger assem ly is a part of the gun bodycasting, it is very diffi-` cult to repack said plunger assembly whennozzle 8 is first removed. Then a small socket wrench is introduced tounscrew andfree the packing gland 27. Thereupon the plunger 26, gland27, spring 28 and guide 28 may all be withdrawn through the muzzle ofthe barrel.

The last point to which attention is directed relates to the novelremovable arrangement of the air control assembly. It is common practicein gun assembly to have the air valve with its seat', a part of the bodycasting. This requires the operatorwhen ordering anew valve stem, to dohis own grinding to seat the valve; but when, as in our gun, the wholecartridge-like assembly of the air valve control is removable, themanufacturer can ship the complete assembly ready for a novice toinsert.

It will be seen by reference to Fig. 1- that the entire assemblycomprising the connection 17, the valve-seat member 16, with its packinggland 18, and the plunger stem 21 with its cup 24 and spring 22, may bereadily removed and replaced, thus facilitating the operation ofgrinding, adjusting and pack- In Fig. 6 we show a structuralmodification of the nozzle which in this instance comprises two members,the outer member 8 which carries the opposingair ducts 13, and the innermember 8 which carries the tip or outlet nipple 10 slidably fitted inlthe outer member. The outer member is screwed upon the muzzle of thebarrel 1 and its air .ducts communicate with the air passage 14 of saidbarrel. The inner member is screwed into the barrel and communicateswith its material chamber. These two members therefore are relativelylinearly movable, whereby the air jets from ducts 13 may be adjustedwith relation to the material jet and to the tip or nipple 10 as may bedesired.

In this modified form of the nozzle the relative linear adjustment ofthe two members 8 and 8 provides, by changing the position of theissuing air jets lengthwise with respect to the tip 10 o r to thematerial jet or stream issuing therefrom, for not only varying andadjusting the width of the fan and the atomizing eect, but also, whenadjusted to the position shown in this Fig. 6, it serves to keep the tipclean at all times.

1. In a spray-gun, a unitary spray-head comprising a nozzle having athrough bore and a discharge orifice solely for the material to besprayed, said nozzle having in its wall a pair of oppositely 4disposedlongitudinally directed air ducts, the forward portions of said ductsconverging on lines inclined to and intersecting the plane of the nozzleorifice whereby the material to be sprayed and air are first broughtinto contact at the point of intersection of the air ducts with thematerial stream.

2. In a spray-gun, a unitary spray-head comprising a nozzle having athrough bore and a discharge orifice solely. for the material to besprayed, said nozzle having in its wall a pair of oppositely disposedlongitudinally -directed air ducts, the forward portions of said ductsconverging on lines inclined to and intersecting the plane of the nozzleorifice, in immediate proximity to said orifice whereby the material tobe sprayed and air are first brought into contact at the point ofintersection of the air ducts with the material stream.

3. In a spray gun, a unitary spray-head comprising a nozzle having anaxial bore, the forward end of said nozzle being formed with a concavityand with a discharge nipple projecting into said concavity, and saidnozzle having in its wall a pair of oppositely disposedlongitudinallydirected airducts, 9

opening into said concavity, the forward portions of said ductsconverging on lines inclined to and intersecting the plane of thedischarge nipple whereby the material to be sprayed and air are firstbrought into contact at the point' of intersection of the air ducts withthe material stream.

4. In a spray gun, a unitary spray-head comprising a nozzle having anaxial material discharge bore, the forward end of said nozzle beingformed with a concavity and with a discharge nipple projecting into saidconcavity, and said nozzle having in its wall a pair of oppositelydisposed longitudinally directed air-ducts, opening into said concavity,the forward portions of said ducts converging on lines inclined to andintersefting the plane of the discharge nipple in immediate proximity tothe forward edge' of said nipple whereby the material to be sprayed andair are first brought into contact at the point of intersection of theair ducts with the material stream.

5.l In a spray gun having a body including a barrel provided withconnections and passages for the material to be sprayed and for the air,respectively, a control mechanism for said material and air comprising amaterialdischarge control plunger disposed longitudinally within thebarrel; an air-inlet control plunger disposed longitudinally within thebarrel; and aligned with the material-,discharge control plunger; atrigger member fitted in the body of the gun; and means, associated withthe adjacent ends of the two plungers, adapted to besuccessively-engaged by the trigger, to move said plungers in timelysuccession, consisting of a cup carried by the air control plunger, anda head on the material control plunger housed within'said cup andlongitudinally slidable therein.

6. In a spray gun having a body including a barrel providedwithconnections and passages for the material to be sprayed and for theair, respectively, a control mechanism for said material and aircomprising a material-discharge control plunger disposed longitudinallyWithin the barrel; an air-inlet control plunger disposed longitudinallywithin the barrel, and aligned with the material-discharge controlplunger, a trigger member fitted in the body of the gun; and means,associated with the adjacent ends of the two plungers, adapted to besuccessively engaged by the trigger, to move said plungers in timelysuccession, consisting of a cup carried by the air control plunger, anda head on the material control plunger housed wit-hin said cup andlongitudinally slidable therein, said cup being adjustably fitted uponsaid air control plunger.

7. In. a spray gun having a body including a barrel provided withconnections and passages for the material to be sprayed and for the airrespectively, a control mechanism forsaid material and air comprising amaterial-discharge control plunger disposed longitudinally within thebarrel; an air-inlet control plunger disposed longitudinally with- .in'thebarrel and aligned with the materialdischarge control plunger; a cupfitted upon .the inner end of the air control plunger; a

head on the inner end of the material control plunger housed within saidcup and longitudinally sli'dably therein; and a trigger piyoted Within'the gun body, said trigger being forked past said cup and head andadapted for successive engagement therewith for the purpose described.

8. In a spray gun, the combination of independent aligned, normallyclosed materialjdischarge control and air inlet control plungers; a cupfitted upon the end of the air control plunger; a head on the adjacentend of the material control plunger, said head lying and adapted forsliding movement within said cup; and a bifurcated trigger forsuccessively engaging said cup and said head.

9. In a spray gun having a barrel, a valveseat' member removably fittedin the heel of the barrel and carrying on its rear end a removablefitting for connection with a source of air, the forward end of saidmember being recessed; packing carried in said recessed end; acontrol-plunger stem removably carried by and slidable'linearly in saidmember and packing; a control valve on said stem; and means foroperating said stem to open and close the valve.

10. In a spray gun having a barrel, a valveseat member removably fittedin the heel of the barrel and carrying on its rear end a reof air, theforward end of said member being recessed; packing carried in saidrecessed end; a control-plunger stem removably carried by and slidablelinearly in said member and packing; a control Valve on said stem; andmeans for operating said stem to open and-close the valve, consisting ofatrigger fitted in the gun barrel, and a spring carried by the stem.

11. In a spray-gun having a body including a barrel member provided withconnections and passages for the material to be sprayed and for the air,respectively, a sprayhead in the form of a unitary member comprising anozzle portion fitted in the muzzle of the barrel, the central bore ofsaid nozzle portion communicating only with the material passage of thebarrel, said unitary meniber having also two air ducts disposedoppositely with relation to each other, said air ducts communicating attheir rear ends only with the air passage of the barrel and affordingthe sole outlet therefrom, and converging at their forward ends on linesinclined to and intersecting the planeof the discharge orifice of thevnozzle.

12. In a spray-gun having a body including a barrel member provided withconnections and passages for the material to be sprayed and for the air,respectively, a sprayhead in the form of a unitary member conlprising anozzle portion fitted in the muzzle of the'barrel, the central bore ofsaid nozzle portion communicating only with the material passage of thebarrel, said unitary meniber having also two air ducts disposed oppo--sitely with relation to'each other, said air ducts affording the soleoutlet for the passage through said sp-ray-head and converging at theirforward ends on lines inclined to and intersecting the plane of thedischarge orifice-of the nozzle portion and in imm ediate proximity tosaid orifice.

13. In a spray-gun having a body including a barrel member provided withconnertions and passages for the material to be sprayed and for the air,respectively, a sprayhead in the formr of a unitary-member conlprising anozzle portion fitted in the muzzle of the barrel and adapted for axialrotary adjustment therein, the central bore of said nozzle portioncommunicating with the material passage of the barrel, said unitarymember having also two air ducts disposed oppositely with relation toeach other, said air ducts at their rear ends 'affording the solecommunication with the air passage of the barrel, and converging attheir forward ends on lines inclined to `and intersecting the plane ofthe discharge orifice of the nozzle.

In testimony whereof we .have signed ouiI names to this specification.

FRANK A. TITTEMORE. CHARLES S. RENWICK.

